The suit, filed by Walther Weiland in an Oakland federal court, says Officer Kevin Mansourian intentionally rammed into Weiland's car, broke his arm and bruised his ribs on Feb. 17 near Orinda. It seeks unspecified damages and names the city of Concord, police Chief Guy Swanger and Mansourian as defendants.

According to the suit, Weiland was driving in heavy traffic on westbound Highway 24 approaching the Caldecott Tunnel; as cars began to merge into his lane, Mansourian cut him off, causing Weiland to slam on his brakes. Weiland attempted to pull around Mansourian, but the off-duty officer struck his car, according to the lawsuit.

When the retired Oakland resident got out of his car to exchange insurance information with Mansourian, the officer allegedly said, "What the (expletive) are you doing? I'm an off-duty police officer!"

The off-duty officer then restrained Weiland until a California Highway Patrol officer arrived and handcuffed him, the suit said. During the incident, Weiland said, he suffered a broken right arm, bruised ribs and cuts and bruises to his face.

Concord City Attorney Mark Coon would not comment on the litigation, saying he has not yet reviewed it. It is also the city's practice not to comment on pending litigation. The Contra Costa County Sheriff's Office investigated the incident, and prosecutors decided not to file charges, Coon said.

Mansourian, a five-year veteran of the Concord Police Department, remains on the force, Coon said.